Sound-amplifying device



Aug. 16, 1927. 1,639,048

B. F. MIESSNER SOUND AMPLIFYING DEVICE Filed June 4, 1923 2 Sheets-Sheetl Aug. 16, 1927. 1,639,048

I B. F. MIESSNER ne 4, 1923 2 Sheets-SheetZ 8140214 to z E Begam/n [Al/8.5500? $51 A attom tmr Patented Aug. 16, 1927.

UNITED QSTATES BENJAMIN F. MIESSNER, OF SOUTH ORANGE, NEW JERSEY.

I SOUND-AMPLIFYIN G DEVICE.

Application filed June 4, 1923. Serial No. 643,152.

This invention relates to sound amplifying devices. More specifically it relates to devices adapted to receive sound waves from a sound reproducing machine and to amplify such sound waves.

The invention has for some of its ob]ec ts: to provide a sound amplifying device whlch is compact, eflicient in amplifyin faithful in tone transmission, which may e manufac tured at a comparatively low cost, and WhlCh is nevertheless ornamental, Other objects and advantages will appear as the inventionis hereinafter disclosed. I I D Referring to the, drawings which illustrate what-I now consider a preferred form ofthe inventionifi f g I F-igL. 1, is a, front elevation of a sound amplifying device. I I

Fig. 2'is a plan view of the device shown in Fig. 1.

F igl 3 is a sectioutak e n substantially on the line 3-3" of jFig'. V l is a section the line. ,4-4 of Fig. t

The: sound amplifying idevice illustrated comprises generallya body 'portlon 10 and a base or pedestal'll for supporting the same and, to jvhich the vbody portion is suitably seeured- The bodyportioii is 'shown con;- structed inl'ItwoYoutwardlyf bulgedf or convexed sections". 12;}.13,',' 'vvhiql1 join substantiallv en a planeperpeifdicular ,to the'axis of the-body portion andhthro'ugh the line 3-3 .of-Fig. 4. Th'section or front wall 12 is shown provideduadjacent its periphery with. anf annular series of radialfslots 14 which, as will hereinafter appear, constitute outlet means or openings through which the sound waves leave the body portion of the device. The sound. Wavesto be amplified are introduced into the body portion 10 substantially centrally thereof. While other forms of means, such as a suitable tube or conduit leading from the sound box of a phonograph or similar sound-reproducing machine. may be employed for supplying the sound waves to be amplified, to the body portion 10. I have selected forthe-purpose of illustration a means especially adapting the invention for use in connection with the amplification of sound waves emanating from a translating device which receives electrical undulations and converts them into sound vibrations. This means, desig nated 15 (Fig. 4) consists of a device comprising one or more polarized electromagneed not be herein disclosed in detail.

current may be suppliedto the device 15 through any suitable conductors (not shown).

The translating device 15 is shown mounted in a suitable recess 16 provided in the rear face of the front wall 12. A comparatively short section of divergent or frustroconical tube 17 is shown connected to the device 15' to convey the sound waves therefrom. This tube is shown surrounded by an annularmember 18 in order to provide a sound-conveying passage of proper and preferred form as will hereinafter appear. The inner face'of the rear wall 13 is provided with an annular or cup shaped partition 19 having asubst-antially conical but curved surfaced boss 20 at its closed end to deflect the soundwaves emanating from the tube 17 and impinging upon the closed end of the cup of the member 19, substantially equally in all radial directions.

" It will be noted that the partition 19 ex- The tends from the rear wall 13 toward the front wall 12 but terminates short of the latter. The partition 19 'is surrounded by an annular or cup-shaped partition 21 which is carried by the front wall 12 and extends toward the rear wall, terminating short of the latter. The partition 17-18, the partitions L'to'get-her with the front and W rear walls '12,f13, of the body portion 10. define a plurality of serially. connected, sound-conveying passages or paths 25 26 27 and 28. The path or passage 28'surrounds the path 27, the path 27 surrounds the path a ueme iee stantially the same direction a's the direction of passage through the tube 17',tnence Into and through the passage 28 in the opposite direction and thence: out through-the open.- ings 14.

Referring to Fig. 1 it Will ='lje" seenthat the cross-sectional area of tbe passage or path 27 is representedby'the following formula: V 3,1416 R= -r= which may be written:

'3.'1416 (R+r)- (It-r).

If each of the annular passagesorpath's 26,

2T=and 28 were so constructed as to be of constant crossriecti on throughout its length, i.' e. Rr)"a constant, and if the difference between the. radii (R,' 'o f any o f these three paths were the same as-th'at 'of',either a (length sub h w E e et;

While ,et iii be adopted in the :QI 1. futionlof ,tli e bQdY p012 tion 10,1 have found'that; jtfisfaetoryi results may be obtained ICO JS I ing be' Sections 12, I3 ;of i \'veo 'c l;by]tuxin tlfr'einfabout'the axis A'A;I('Fig, ember 18 may also be inadebf med utned, 'on a. lathe or; othe gsuit'abl QWO k-mg; ma hilie- Tlie slots fl'tiit t h'e'n through the front wall- 12;; l hejtranslatingid 'ee115is th n mounted initlie recess '1 and suitably secured therein; The tube litisltlierj l 'inscrtedinto the bore of 'tlie'me nber 1S'and the tubesecured to thedevice 15. Tlie seetion s12, 13 are then secured togetlieriatltl'ieir facing marginal1edges,.th us eompletingthe-body portion 10' To facilitate 'as'sembly, alignment and the connectionof the sections 12, 13, the Section 12 may be-providedfirith an annular recess 30 to receive a mating annular bead 31 provided on the section-13; The body portion may-be secured'to the base or pedes tal 11,- which may also be constructed of wood;- by any suitable means;

Assuming that the sound amplifying device istube-employed in connection with a radio telephony receiving apparatus the conductors or leads-"(not shown) of the device 15 are electrically connected to the terurinals to which loud speakers now com? nionly in use are connected. If desired, the device 15 may be suitably connected to a microphone device having a stylus adapted to engage and be vibrated by the undulations in the record gr'ooveof a disc or other record of a phonograph or other sound reproducing n'lach'ine Or,'as stated above, sound waves may beintroduced into the body portion by a conduit leading from the sound box of a phonograph or similar sound-reproducing machine.

Instead of constructing the body I portion 'antlpedestaljll of wood, either .or both l'riay be constructed of other suitable material. on example, either or both ofjthe bedy'po'rtio'n 1 0 and 'base llniay be molded or pressed or otherwise formed "of jpa'pierni'fi c'hfrvood pu'lp."or"otl1er suitable liquid 9, pla i m ia V. f f

In accordance with the, provisio ns of the e ee stetetes, lhei ther d' the prinei reof'opemien of my invention, tot r w t eeppere f lh hl'ln sider to" represent ,the best embodiments l hfllisi but I d sire to have it -u n derstoo'd may {the disclosed 'i'sfonly illustratiie and that the intention can be carried e. b' f thsiffi e i s lA i wh l it is id ied 'f to: se' the gl arijonsf features and ele iiientsiflin tliefcoinbijnationsand relations deso'rneof 'thesefmay" be altered. and ptlier's ;1 1i't' tec1' a'nd ls om'e of the features of eacltf modification may be embodied in the others: without interfering with the more s e r ts o. 1t1. e a d' e i nt n c ured"to and supported by the front outer end of 'said casing for supporting said seccud-mentioned means andpermitting the vex casing provided with anannular series of sound-discharging 'openlngs adyacent: the

periphery of its frontwall, apairof radially and endwise spaced .annularipartitions one of whichissecured to and carried by 'the:rear

wall and extends toward: the 'fro ntwall and the other-ofwhich is secured to and carriedi by the front- .wallrandextends toward :the rear wall and -surrounds=.=tl1e \partition i-secured to the rearzs-walhsthe twopartitions:

and: the casing cooperating tozdefine a:tort u..

ous sound-conveying passage whichzhas tions which increase inpcr ossrsectional area: in the direction lin which sound; traigels :t'o ward thelsound dischargingopenings ia-nd! means -including;a translating device-:supported by: 'oneof :the wallsio'fithe casing'afor;

' supplying sound ;waves' itjol. ;th e inlet :end of.

that portion of thesound-convey-ing passage: which isdefinedQby the-:inner. wall'of the; partition which is secured: ,to gthe rear. walls.

A- sound'amplifying' devicer'comprising in combination,ia'ecasing including algfront, wall whose outer,,surface is-convcxiat'its cen tral portion and PIOVldQd withwanannular series of; sound-discharging 3 ppenings; adj acent its periphery, and .a rear wall havingga convex outer surface which bulges away. from the front vwall,.- the. front .wallbeing provided with. a rim portiomwhich. connected tot;he. rim .portionofgthe rear wall, ja pair-,of radiallyand endwise spaced, annular partiv tions one .ofwhich is secured to the rear wall and-extends toward ,tllQjijQQt wall andthe other of-which is-securedto ,the front wall and extendsv toward .the;re ar wall ,and; surrounds the partition secured .tdtherear wall, the two partitions and the casingcooperating to define a tortuous sound-conveying passage which has sections which in crease in cross-sectional area,in-theydirec- Lion in which sound travels toward the sound discharging opening, and means for supplying sound waves to' theinlet end of that portion of the sound-conveying;p assage which is defined by the inner v wall oj the partition which is secured to;th e' rear wall; A sound amplifying device compris ing, in combination;,a casing including a. front wall whoseoutersurface is convex at its central portionand provided with an annular series of sound-discharging ,openings adjacent its periphery, and arealwall .hav ing a convex outer surface which bulges away from the frontwall, the front wall being provided with a rim portion whiclris connected to the rim portion of thesrear wall; a pair of radially. and vendwis e spaced annular partitions one of which is secured to the rearwalland extends'toward the front wall and the other of which is secured to the front walland extends toward the rear wall and surrounds the partitionsecured to the rear wall; the two partitions. and the casing cooperating to define atortuous sound-conveyingl passage which has sections which .increase;inucross-sectional;area in the direction in which sound travels toward the sound discharging openings, means for supplying sound waves .up to the-inlet end of thatportion; of the. .isound-vconveying passage which iszdefined by-the innerwall of the artition whichis-'secured;tothe rear' wal'l,-an a supportingbase securedto the periphery of the 5 U 1 r i1;-

5.- =An sound amplifying. device comprising incombination, a} casing including a ,frontwall ;;;Wl1o'se;jo futer.- surfacev -is; convex. at its central portion and provided with an annularseries of;,sound-dischargingopenings adj acentr itsi periphery, and-a rear wall having a convex outer surface which bulges away fromj the front ;wall', the front wall being provided with a rim portion-whichis connected to the rim portion offthe rear wall, a :paipof radially and endwise, spaced nnnular partitions one of which is secured to therear .wall and extends toward @the: front wall and; the other of which is secured to the front wall and extends toward the rear wall and: surrqinndsthepartition secured to the rear wall,- -,the;; two partitions-and the casing cooperating to. define a tortuous s0und-co nveyingpassage which has. s ec tions Y which increase in cross-sectional area in the direct-ion;nin twhicli .sound travels toward the sound discharging openings, meansiincluding a translating device supported by one of said walls for supplying sound waves to the-inlet endof that portion of the sonnd conveying passage which is defined by the inner wall of,the partition which is secured to the rear wall, and a supporting base secured to the periphery of the casing.

.6. .A sound amplifying device comprising in combination, a casing including a front wall whose outer surface is convex atits central portion and provided with an annular series of sound-discharging openings adjaoentits periphery, and a rear wall having a convex outer surface which bulges away from thefront' wall. the front wall being provided with a rim portion, which is connected to the rimportion of the rear wall, a pair of radiallyj and'en dwise spaced annular partitions one of'which is secured to the rear wall and extends toward the front wall and the other of'which is secured to and carried byvthe front wall and extends toward the rear wall and surrounds the partition sccured to the rear wall, thetwo partitions and the casing cooperating to define a tortuous sound-conveying passage which has sections which increase in cross-sectional area in the direction in which sound travels toward the sound discharging openings, means including a translating device supported by one of said walls for supplying sound waves to the inlet end of that. portion of the sound-conveying passage which is defined by the inner -wall of the partition which is secured to the rear wall, and a supporting base secured to the periphery of the casing.

7. A sound amplifying device-adapted to be employed in connection with a radio telephony receiving apparatus and comprising in combination; a casing including a front wall whose outer surface'is convex at its central portion and provided with an anuular series of sound-discharging openings adjacent its periphery, and a rear wall having a convex outer surface which bulges away from the front wall, the front wall being provided with a rim portion which overlaps wall and extends toward the front wall andthe other of which is secured to and carried by the front wall and ext'endstoward the rear wall and surrounds the partition secured to the rear wall, the two partitions and the casing cooperating to define a tortuous sound-conveying passage -which has sections which increase in crosssectional area in the direction-in which sound travels toward the sound discharging openings, means including a translating device supported by one of said walls for supplying-sound waves to the inlet end of that port'ioii-of'the sound-- conveying passage which is defined by the inner wall of the partition which is securedto the rear wall, and asupporting'base secured to the periphery of the casing.

8. A sound amplifying device adapted to be employed inconnection' -with a'radio telephony receiving apparatus andcomp'rising in combination; a casing includingafront wall whose outer surface 15 convexat its central portion and, provided with air-annula-r series of sound-dischargingopenings a djacent its periphery, and a' rearwan having a convex outer surface WhichJbuIges away from the front wall, the front'wall'beingf provided with a rim portion Which-overlaps and is secured to the rim portionfofi rear wall; a pair of radially andfeiidvvi gb 'df annular partitions one of which is securedto' and carried by the rear wall and extends.

toward the front wall and the other of whichj is secured to and carried by the front'wall' and extends toward the rear wall and sur rounds the partition secured to the rear wall,

the two partitions and the casing cooperae ing to define a tortuous sound c'o'nveying' passage which'has sections which increase in cross-sectional area in the direction in which sound travels toward the sound dis charging openings, and means including a translating device supported by the front wall of.the casing for supplying sound wavesto the inlet end of that portion of the sound-conveying passage which is defined by the inner wall of the partition which is secured to the=rear wall;

9. A sound amplifying dev-ice'adapted to be employed in connection with a radio telephony receiving apparatus and comprising in combination acasing including a front wall whose outer surface is convex at its central port-ion and provided with an au-. nular series of sound-discharging openings adjacent its periphery,- and a rear wall havinga convex outer surface which bulges away from the front wall, the front wall being provided with a rim portion which overlaps and: issecured to the rim portion of the rear wall, the front and rear walls consisting of molded fibrous material; a pair of radiallyand endwise' spaced annular partitions one -ofwhich is-securedto and: car-. ried by the rear wall and'extends toward the front wall and the-other of which is secured to and carried by the front wall and extends toward'the rear wall and-surrounds the partition secured to the rear wall, the two partitions and' the; casing cooperating to define a tortuous-sound conveying passage which has annu-lar sections which increase in radial width in the directionin which sound travels'toward the sounddischarging openings,-=means1including a translatingdevice supported by one of said walls for sup plying sound waves to the inletend of .that portion of the sound-conveying passage whi'clris' defined by the inner-wall of the partitioh wliich'i's' secured to the rear-wall; and-as'upporting base'secured' to the periphcry of the casing;

1-0; a t-"sound amplifying-device adapted to be employed in connection with a radio tel'ephony receiving apparatus and comprising incombination {acircular casing whose axial dimension is substantially less than'its diameter and including a front wall whose outer surface is convex at its 'central'portion and provided,'vvith an'annular 'series of 'sound-' discharging openings adjacent i ts periphery, and'a rear wall having a convex outer surface whicl'if'bul'ges away from the front wall, the =front'wall' being provided. with a rim portion which overlaps and is secured to the rim portion ofthe rear wall, a plurality of partitions including a pair of radially and endwise spaced partitions one of which is secured to and carried by the rear wall and extends toward the front wall'and'the other of which air is secured to and carried by the front wall and extends toward the rear Y Wall and surround s'th'e partition secured to the rear wall, the partitions and the casing cooperating to define a tortuous sound-conveying passage which has sections which increase in cross-sectional area in the direction in which soun-ii travels toward the sound-discharging openings means includ ing a translating device supported by one of said walls for supplying sound waves to the inlet end of that portion of the sound-conveying passage which is defined by the inner wall of the partition which is secured to the rear wall, and a supporting base secured to the periphery of the casing.

11. A sound amplifier comprising in combination; a circular casing whose axial dimension is substantially less than its diameter; means within said casing providing a forwardly flaring axial passage; means including a rearwardly-extending partition member forming a passage surrounding the axial passage and communicating with the forward end thereof and extending rearwardly and outwardly therefrom, and a sound delivery passage surrounding the second said passage and communicating with the rear end thereof and extending forward therefrom and means secured to the forward end of said casing and extending across said sound-delivery passage at its forward outlet end for supporting said rearwardly-ex tending partition member from said casing.

In testimony whereof I hereto afiix my signature.

BENJAMIN F. MIESSNER. 

